An optical network, such as a passive optical network (PON) as an example, often delivers voice, video and/or other data among multiple network nodes. In the case of a PON, the network nodes are often referred to as optical network terminals (ONTs). The PON can deliver data among multiple ONTs using a common optical fiber link. Passive optical splitters and combiners enable multiple ONTs to share the optical fiber link. An optical line terminal (OLT) transmits information downstream to the ONTs, and receives information transmitted upstream from the ONTs. Each ONT terminates the optical fiber link for a residential or business subscriber, and is sometimes referred to as a subscriber or customer premises node.
Each ONT is connected to one or more customer premises equipment (CPE) devices, which ultimately receive the voice, video and other data delivered via the PON. Examples of CPE devices include computers, telephones, television set-top boxes or the like. An ONT on a PON may receive traffic from several sources. Some sources may be commonly used among several ONTs on a PON. For example, several ONTs may access a common traffic flow associated with switched digital video (SDV) or other multicast streams. Other sources may produce traffic flows that are unique to an individual ONT. For example, an individual ONT may receive web content from an Internet service provider (ISP) or voice data from the public switched telephone network (PSTN).
Delivery of data from a given OLT to multiple ONTs often involves replication of data packets. For example, multiple ONTs may each service subscriber stations that have joined a given multicast group that provides the same video, audio or other data to each of the subscribed subscriber stations. The OLT receives this multicast data in the form of a stream of multicast packets and replicates each of these multicast packets to create a copy for each ONT having a (CPE device that has joined the multicast group. The OLT then sends the copies of the same multicast packet to each of the respective ONTs. The ONTs, upon receiving the copy, send the copy of the packet to the corresponding one of the CPE devices, whereupon the CPE device consumes the multicast content.